Hirschsprung disease, associated syndromes and genetics: a review

Prevalence and network structure of depression, anxiety and adverse doctor-patient relationship risks among patients with physical diseases: A cross-sectional study

BACKGROUND

Mental health issues among patients with physical diseases are increasingly common. This study investigated the prevalence of depression, anxiety, and adverse doctor-patient relationship risks (ADRR) among patients with physical diseases, and the central and bridge symptoms of this network structure.

METHODS

A total of 14,344 patients with physical diseases enrolled in this survey. The Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), and Psychological Safety Questionnaire were used to evaluate anxiety, depression, and ADRR. The "qgraph" package in R 4.4.3 was used to construct a network model to identify central and bridge symptoms.

RESULTS

The prevalence rates of depression, anxiety, and ADRR were found to be 9.52 % (95 % confidence interval (CI): 9.04-10.00 %), 19.35 % (95 % CI: 18.71-20.00 %), and 4.29 % (95 % CI: 3.96-4.62 %), respectively. Within the network structure, the central symptoms identified were 'Sad mood,' 'Restlessness,' and 'Excessive worry,' which also served as the bridge symptoms. The flow network analysis revealed that ADRR exhibited the strongest associations with 'Anhedonia', 'Restlessness', and 'Suicidal ideation'. Additionally, 'Suicidal ideation' shows strongest correlations with 'Guilt', 'Concentration', and 'Restlessness'.

LIMITATION

The generalizability of the study's findings is constrained, as the sample consisted exclusively of inpatients, potentially limiting applicability to non-hospitalized individuals with physical illnesses.

CONCLUSION

This study provides novel insights into the comorbidity of depression, anxiety, and ADRR at the symptom level in patients with physical diseases through the application of network analysis. The identification of bridge symptoms highlights potential targets for interventions aimed at addressing the comorbidity among these disorders.

Variability in proliferative and migratory defects in Hirschsprung disease-associated RET pathogenic variants

Hirschsprung disease (HSCR) exhibits extensive genetic heterogeneity, with 72% of cases involving pathogenic variants in 10 genes forming a gene regulatory network (GRN) essential for enteric nervous system (ENS) development. The receptor tyrosine kinase gene RET is the most significant contributor, implicated in 12%-50% of individuals depending on the phenotype. RET plays a critical role in ENS precursor proliferation and migration, and defects in these processes lead to HSCR. However, the functional impact of RET pathogenic variants and their mechanisms of disease remain poorly understood. To address this, we investigated proliferative and migratory phenotypes in a RET-dependent neural crest-derived cell line harboring one of five missense (c.166C>A [p.Leu56Met]; c.532G>C [p.Glu178Gln]; c.2372A>T [p.Tyr791Phe]; c.2765C>A [p.Ser922Tyr]; or c.2994T>A [p.Phe998Leu]) or three nonsense (c.612C>A, c.2308C>T, or c.2943C>G) heterozygous pathogenic RET variants. Using cDNA- and CRISPR-based prime reverse insertion mechanism engineering (PRIME) editing coupled with quantitative proliferation and migration assays, we observed significant losses in proliferation and migration in three missense (c.612C>A [p.Tyr204∗]; c.2308C>T [p.Arg770∗]; and c.2943C>G [p.Tyr981∗]) and all nonsense variants. Notably, the c.2372A>T (p.Tyr791Phe) missense variant, whose pathogenicity has been debated, appears benign. Importantly, the severity of migration loss did not consistently correlate with proliferation defects, and the phenotypic severity of nonsense variants was independent of their position within the RET protein. This study highlights the necessity of targeted functional assays to accurately assess the pathogenicity of HSCR-associated variants rather than relying solely on bioinformatics predictions, which could be refined by incorporating functional data.

Multi-ancestry genome-wide association meta-analysis identifies novel associations and informs genetic risk prediction for Hirschsprung disease

BACKGROUND

Hirschsprung disease (HSCR) is a rare, congenital disease characterized by the absence of enteric ganglia in the hindgut. Common genetic variation contributes substantially to the heritability of the disease yet only three HSCR-associated loci were identified from genome-wide association studies (GWAS) thus far.

METHODS

We performed the largest multi-ancestry meta-analysis of GWAS to date, totalling 1250 HSCR cases and 7140 controls. Prioritized candidate genes were further characterized using single-cell transcriptomic data of developing human and mouse gut for their roles in development of enteric nervous system (ENS). Functional characterisation using human cells and zebrafish models was performed. Global and ancestry-matched polygenic risk score (PRS) models were derived and evaluated for predicting risk of HSCR.

FINDINGS

We identified four HSCR-susceptibility loci, with three loci (JAG1, HAND2 and ZNF25) reaching genome-wide significance and one putative locus (UNC5C) prioritized by functional relevance. Spatiotemporal analysis revealed hotspots of gene dysregulation during ENS development. Functional analyses further demonstrated that knockdown of the candidate genes impaired cell migration and zebrafish knockouts displayed abnormal ENS development. We also demonstrated comparable performance for a PRS model derived from multi-ancestry meta-analysis to those of ancestry-matched PRS models, supporting its potential clinical application in risk prediction of HSCR across populations.

INTERPRETATION

Overall, the meta-analysis implicated novel genes, pathways and spatiotemporal developmental hotspots in the genetic aetiology of HSCR. Development of a PRS universally applicable irrespective of ancestries may leverage its clinical utility in risk prediction.

FUNDING

The full list of funding bodies can be found in the Acknowledgements section.

Histopathologic Concerns and Diagnostic Challenges in Hirschsprung's Disease: An Eastern European Single-Center Observational Study

BACKGROUND

We proposed a comprehensive clinicopathological study involving the characterization of the study cohort and a comparative analysis of biopsies and surgical specimens from patients with Hirschsprung's disease. The study was complemented by the diagnostic value of calretinin, CD56, and S-100 immunohistochemistry.

METHODS

Descriptive statistical analysis of diagnostic variables in the group of biopsy specimens (n = 32) and bowel resection specimens (n = 16) was performed. The pattern of calretinin and CD56 expression in Meissner's plexus elements was analyzed and the maximum thicknesses of the nerve fibers were measured using morphometry with S100-immunostained sections.

CONCLUSIONS

Coupled calretinin-CD56 immunohistochemistry is useful in diagnosing ganglion cell paucity biopsies or specimens with incomplete submucosa. In cases where there are no ganglion cells but there are calretinin-positive nerve fibrils in the lamina propria without nerve trunk (NT) hypertrophy, re-biopsy is the best solution. The significant differences in NT size between biopsies and surgical specimens highlight the importance of assessing NT diameter in all tissue samples examined.

Scientific evolution from the definition of Hirschsprung disease to the present: a bibliometric analysis (1980-2023)

BACKGROUND

The primary objective of this study is to define the global productivity of Hirschsprung disease (HSCR), identify influential studies, determine research directions focused on both historical and contemporary perspectives.

METHODS

The study obtained 2816 articles published between 1980 and 2023 related to HSCR from the Web of Science database, and comprehensive bibliometric analysis were conducted.

RESULTS

The top three most productive countries were the USA (n = 1283), China (n = 1167), and Japan (n = 587). The most productive institution was Université Paris Cité (n = 149), and the most productive author was Prem Puri (n = 99). The most frequently used keywords in the articles were enterocolitis (n = 191), enteric nervous system (n = 136), and transanal endorectal pull-through (n = 129).

CONCLUSION

Academic interest in HSCR began in 1887-1888, significantly increased in 1948 and 1964, and reached its highest peak in 1994. The findings indicate that key topics such as enterocolitis, enteric nervous system, surgical techniques, and genetic factors have been prominent in HSCR research. Previous studies, which often focused on molecular and genetic mechanisms, have shifted towards clinical and surgical applications in the last decade. Factor analysis reveals the complexity and diversity of HSCR research, with various topics examined, including clinical features, surgical treatments, pathological findings, and genetic bases.

IMPACT STATEMENT

This study presents a comprehensive bibliometric analysis of global research trends and future directions in Hirschsprung disease, revealing significant changes and developments in the study of the disease. The study provides an important contribution to the existing literature by detailing the historical development, main research topics, and thematic evolution of Hirschsprung disease research. The findings indicate that future research focus in Hirschsprung disease may increasingly prioritize innovative approaches, such as stem cell therapy, alongside clinical and surgical advancements. These advancements have the potential to enhance patient quality of life and guide future research strategies.

Dietary manipulation of intestinal microbes prolongs survival in a mouse model of Hirschsprung disease

Enterocolitis is a common and potentially deadly manifestation of Hirschsprung disease (HSCR) but disease mechanisms remain poorly defined. Unexpectedly, we discovered that diet can dramatically affect the lifespan of a HSCR mouse model ( Piebald lethal , sl/sl ) where affected animals die from HAEC complications. In the sl/sl model, diet alters gut microbes and metabolites, leading to changes in colon epithelial gene expression and epithelial oxygen levels known to influence colitis severity. Our findings demonstrate unrecognized similarity between HAEC and other types of colitis and suggest dietary manipulation could be a valuable therapeutic strategy for people with HSCR.

Abstract

Hirschsprung disease (HSCR) is a birth defect where enteric nervous system (ENS) is absent from distal bowel. Bowel lacking ENS fails to relax, causing partial obstruction. Affected children often have "Hirschsprung disease associated enterocolitis" (HAEC), which predisposes to sepsis. We discovered survival of Piebald lethal ( sl/sl ) mice, a well-established HSCR model with HAEC, is markedly altered by two distinct standard chow diets. A "Protective" diet increased fecal butyrate/isobutyrate and enhanced production of gut epithelial antimicrobial peptides in proximal colon. In contrast, "Detrimental" diet-fed sl/sl had abnormal appearing distal colon epithelium mitochondria, reduced epithelial mRNA involved in oxidative phosphorylation, and elevated epithelial oxygen that fostered growth of inflammation-associated Enterobacteriaceae . Accordingly, selective depletion of Enterobacteriaceae with sodium tungstate prolonged sl/sl survival. Our results provide the first strong evidence that diet modifies survival in a HSCR mouse model, without altering length of distal colon lacking ENS.

Highlights

Two different standard mouse diets alter survival in the Piebald lethal ( sl/sl ) mouse model of Hirschsprung disease, without impacting extent of distal colon aganglionosis (the region lacking ENS). Piebald lethal mice fed the "Detrimental" diet had many changes in colon epithelial transcriptome including decreased mRNA for antimicrobial peptides and genes involved in oxidative phosphorylation. Detrimental diet fed sl/sl also had aberrant-appearing mitochondria in distal colon epithelium, with elevated epithelial oxygen that drives lethal Enterobacteriaceae overgrowth via aerobic respiration. Elimination of Enterobacteriaceae with antibiotics or sodium tungstate improves survival of Piebald lethal fed the "Detrimental diet".

Graphical abstract

Rdh10-mediated Retinoic Acid Signaling Regulates the Neural Crest Cell Microenvironment During ENS Formation

The enteric nervous system (ENS) is formed from vagal neural crest cells (NCC), which generate most of the neurons and glia that regulate gastrointestinal function. Defects in the migration or differentiation of NCC in the gut can result in gastrointestinal disorders such as Hirschsprung disease (HSCR). Although mutations in many genes have been associated with the etiology of HSCR, a significant proportion of affected individuals have an undetermined genetic diagnosis. Therefore, it's important to identify new genes, modifiers and environmental factors that regulate ENS development and disease. Rdh10 catalyzes the first oxidative step in the metabolism of vitamin A to its active metabolite, RA, and is therefore a central regulator of vitamin A metabolism and retinoic acid (RA) synthesis during embryogenesis. We discovered that retinol dehydrogenase 10 (Rdh10) loss-of-function mouse embryos exhibit intestinal aganglionosis, characteristic of HSCR. Vagal NCC form and migrate in Rdh10 mutant embryos but fail to invade the foregut. Rdh10 is highly expressed in the mesenchyme surrounding the entrance to the foregut and is essential between E7.5-E9.5 for NCC invasion into the gut. Comparative RNA-sequencing revealed downregulation of the Ret-Gdnf-Gfrα1 gene signaling network in Rdh10 mutants, which is critical for vagal NCC chemotaxis. Furthermore, the composition of the extracellular matrix through which NCC migrate is also altered, in part by increased collagen deposition. Collectively this restricts NCC entry into the gut, demonstrating that Rdh10-mediated vitamin A metabolism and RA signaling pleiotropically regulates the NCC microenvironment during ENS formation and in the pathogenesis of intestinal aganglionosis.

Discovery of an Efficacious RET PROTAC Degrader with Enhanced Antiproliferative Activity against Resistant Cancer Cells Harboring RET Solvent-Front Mutations

Rearranged during transfection (RET) kinase is a validated therapeutic target for various cancers characterized by RET alterations. Although two selective RET inhibitors, selpercatinib and pralsetinib, have been approved by the FDA, acquired resistance through solvent-front mutations has been identified rapidly. Developing proteolysis targeting chimera (PROTAC) targeting RET mutations offers a promising strategy to combat drug resistance. Herein, we describe the design, synthesis, and evaluation of a series of RET PROTAC degraders. The representative compound QZ2135 (20) effectively degraded RET kinase and its resistant mutants, such as V804M and G810C/R. It also exhibited superior antiproliferative activity against Ba/F3 cells stably expressing oncogenic fusions of RET with solvent-front mutants, including G810C/R/S, compared to its parental inhibitor. Notably, QZ2135 demonstrated in vivo antitumor efficacy in a Ba/F3-KIF5B-RET-G810C xenograft mouse model. Together, this study provides a potential alternative strategy for overcoming acquired resistance to RET inhibitors mediated by solvent-front mutations.

Gut Neuropathies and Intestinal Motility Disorders

BACKGROUND

The enteric nervous system plays a key role in the coordination of gastrointestinal motility together with sympathetic, parasympathetic, and extrinsic sensory pathways. In some cases, abnormalities in neural activity in these pathways contribute to disorders of gut motility. Where this is associated with damage or death of enteric neurons, usually detected by microscopy, this is considered a gut neuropathy.

PURPOSE

This review summarizes recent advances in the identification of neuropathies in a range of gastrointestinal motility disorders.

The Role of de novo and Ultra-Rare Variants in Hirschsprung Disease (HSCR): Extended Gene Discovery for Risk Profiling of Patients

Background

Hirschsprung disease (HSCR) is a rare neurodevelopmental disorder caused by disrupted migration and proliferation of enteric neural crest cells during enteric nervous system development. Genetic studies suggest a complex etiology involving both rare and common variants, but the contribution of ultra-rare pathogenic variants (PAs) remains poorly understood.

Methods

We perform whole-exome sequencing (WES) on 301 HSCR probands and 109 family trios, employing advanced statistical methods and gene prioritization strategies to identify genes carrying de novo and ultra-rare coding pathogenic variants. Multiple study designs, including case-control, de novo mutation analysis and joint test, are used to detect associated genes. Candidate genes are further prioritized based on their biological and functional relevance to disease associated tissues and onset period (i.e., human embryonic colon).

Results

We identify 19 risk genes enriched with ultra-rare coding pathogenic variants in HSCR probands, including four known genes (RET, EDNRB, ZEB2, SOX10) and 15 novel candidates (e.g., COLQ, NES, FAT3) functioning in neural proliferation and neuromuscular synaptic development. These genes account for 17.5% of the population-attributable risk (PAR), with novel candidates contributing 6.5%. Notably, a positive correlation between pathogenic mutational burden and disease severity is observed. Female cases exhibit at least 42% higher ultra-rare pathogenic variant burden than males (P = 0.05).

Conclusions

This first-ever genome-wide screen of ultra-rare variants in a large, phenotypically diverse HSCR cohort highlights the substantial contribution of ultra-rare pathogenic variants to the disease risk and phenotypic variability. These findings enhance our understanding of the genetic architecture of HSCR and provide potential targets for genetic screening and personalized interventions.

Human Enteric Glia Diversity in Health and Disease: New Avenues for the Treatment of Hirschsprung Disease

BACKGROUND & AIMS

The enteric nervous system (ENS), which is composed of neurons and glia, regulates intestinal motility. Hirschsprung disease (HSCR) results from defects in ENS formation; however, although neuronal aspects have been studied extensively, enteric glia remain disregarded. This study aimed to explore enteric glia diversity in health and disease.

METHODS

Full-thickness intestinal resection material from pediatric controls and patients with HSCR was collected, dissociated, and enriched for the ENS population through fluorescence-activated cell sorting. Single-cell RNA sequencing was performed to uncover the transcriptomic diversity of the ENS in controls and HSCR patients, as well as in wild-type and ret mutant zebrafish. Immunofluorescence and fluorescence in situ hybridization confirmed the presence of distinct subtypes.

RESULTS

Two major enteric glial classes emerged in the pediatric intestine: Schwann-like enteric glia, which are reminiscent of Schwann cells, and enteric glia expressing classical glial markers. Comparative analysis with previously published datasets confirmed our classification and revealed that although classical enteric glia are predominant prenatally, Schwann-like enteric glia become more abundant postnatally. In HSCR, ganglionic segments mirrored controls and aganglionic segments featured only Schwann-like enteric glia. Leveraging the regenerative potential of Schwann cells, we explored therapeutic options using a ret mutant zebrafish. Prucalopride, a serotonin-receptor (5-HT) agonist, induced neurogenesis partially rescuing the HSCR phenotype in ret+/- mutants.

CONCLUSIONS

Two major enteric glial classes were identified in the pediatric intestine, highlighting the significant postnatal contribution of Schwann-like enteric glia to glial heterogeneity. Crucially, these glial subtypes persist in aganglionic segments of patients with HSCR, offering a new target for their treatment using 5-HT agonists.

Novel ganglion cell marker B3GNT6: A step forward in Hirschsprung's disease diagnosis

Hirschsprung's (HSCR) disease, also known as aganglionic megacolon, or congenital intestinal aganglionosis affects roughly 1 out of every 5000 newborns. It is a birth defect characterized by the partial or complete loss of ganglion cells in the myenteric and submucosal plexus of the distal intestine which leads to ineffective peristalsis, constipation, and obstruction. Clinical assessment and radiological observations might imply HSCR disease, but definitive diagnosis requires biopsy interpretation and confirmation of ganglion cell loss. The difficulty in identifying immature ganglion cells added to the variability in interpreting immunohistochemical markers of ganglion cells warrants the search for new markers. Our recent research identified Beta-1,3-N-acetylglucosaminyltransferase (B3GNT6) as a potential candidate, as it consistently stains the cytoplasm of ganglion cells. To evaluate its utility, we conducted a preliminary assessment of B3GNT6 expression in nineteen gastrointestinal tissue samples and observed cytoplasmic staining in ganglion cells across all samples. This consistent staining pattern suggests B3GNT6 could serve as a reliable marker for diagnosing Hirschsprung's disease. This article serves as a preliminary evaluation of B3GNT6 as a ganglion cell immunohistochemical marker, highlighting its potential significance while acknowledging the need for further validation in larger, more diverse cohorts.

Inhibition of Neural Crest Cell Migration by Strobilurin Fungicides and Other Mitochondrial Toxicants

Cell-based test methods with a phenotypic readout are frequently used for toxicity screening. However, guidance on how to validate the hits and how to integrate this information with other data for purposes of risk assessment is missing. We present here such a procedure and exemplify it with a case study on neural crest cell (NCC)-based developmental toxicity of picoxystrobin. A library of potential environmental toxicants was screened in the UKN2 assay, which simultaneously measures migration and cytotoxicity in NCC. Several strobilurin fungicides, known as inhibitors of the mitochondrial respiratory chain complex III, emerged as specific hits. From these, picoxystrobin was chosen to exemplify a roadmap leading from cell-based testing towards toxicological predictions. Following a stringent confirmatory testing, an adverse outcome pathway was developed to provide a testable toxicity hypothesis. Mechanistic studies showed that the oxygen consumption rate was inhibited at sub-µM picoxystrobin concentrations after a 24 h pre-exposure. Migration was inhibited in the 100 nM range, under assay conditions forcing cells to rely on mitochondria. Biokinetic modeling was used to predict intracellular concentrations. Assuming an oral intake of picoxystrobin, consistent with the acceptable daily intake level, physiologically based kinetic modeling suggested that brain concentrations of 0.1-1 µM may be reached. Using this broad array of hazard and toxicokinetics data, we calculated a margin of exposure ≥ 80 between the lowest in vitro point of departure and the highest predicted tissue concentration. Thus, our study exemplifies a hit follow-up strategy and contributes to paving the way to next-generation risk assessment.

Health literacy in parents of children with Hirschsprung disease: a novel study

PURPOSE

To explore health literacy (HL) among parents of children with Hirschsprung disease (HD).

METHODS

Norwegian-speaking parents of children under 16 who underwent HD surgery at a tertiary center were surveyed using the Health Literacy Questionnaire-Parent, electronic Health Literacy Scale, General Self-efficacy Scale, and a study-specific questionnaire. Demographics were collected and ethical approval was obtained.

RESULTS

Among 132 parents (77 mothers) of 91 children (median age 8 years), high HL scores appeared in the domains "understanding health information" and "active engagement", with lower scores in "provider support", "health information appraisal", and "social support". Higher HL correlated with parents aged over 40 and higher education. Lower scores were seen with non-exclusive Norwegian use at home and not living with the child's other parent. High electronic HL scores were common (mean 3.6, maximum score 5). 69% had high self-efficacy scores (score > 2, maximum score 4). Self-efficacy correlated strongly with higher HL scores.

CONCLUSION

Parents of children with HD feel healthcare providers lack understanding of their child's challenges, experience limited social support and struggle with interpreting health information. We suggest targeted HL interventions for young, lower-educated, non-cohabitating parents and those not primarily speaking the official language at home.

The role of G protein-coupled receptors and their ligands in animal domestication

The domestication of plants and animals has resulted in one of the most significant cultural and socio-economical transitions in human history. Domestication of animals, including human-supervised reproduction, largely uncoupled particular animal species from their natural, evolutionary history driven by environmental and ecological factors. The primary motivations for domesticating animals were, and still are, producing food and materials (e.g. meat, eggs, honey or milk products, wool, leather products, jewelry and medication products) to support plowing in agriculture or in transportation (e.g. horse, cattle, camel and llama) and to facilitate human activities (for hunting, rescuing, therapeutic aid, guarding behavior and protecting or just as a companion). In recent years, decoded genetic information from more than 40 domesticated animal species have become available; these studies have identified genes and mutations associated with specific physiological and behavioral traits contributing to the complex genetic background of animal domestication. These breeding-altered genomes provide insights into the regulation of different physiological areas, including information on links between e.g. endocrinology and behavior, with important pathophysiological implications (e.g. for obesity and cancer), extending the interest in domestication well beyond the field. Several genes that have undergone selection during domestication and breeding encode specific G protein-coupled receptors, a class of membrane-spanning receptors involved in the regulation of a number of overarching functions such as reproduction, development, body homeostasis, metabolism, stress responses, cognition, learning and memory. Here we summarize the available literature on variations in G protein-coupled receptors and their ligands and how these have contributed to animal domestication.

Causes and consequences: development and pathophysiology of Hirschsprung disease

Hirschsprung disease (HSCR) is a congenital enteric neuropathy in which the enteric nervous system (ENS) fails to develop along variable lengths of the distal gastrointestinal (GI) tract. This aganglionosis results in a functional bowel obstruction and requires surgical resection of the aganglionic segment. Despite surgery, however, long-term bowel dysfunction affects many patients. Understanding the embryologic causes and pathophysiologic consequences of HSCR is critical to improving its diagnosis and treatment. During normal gut development, the ENS arises from neural crest cells (NCCs) that delaminate from the neural tube to populate the entire GI tract with enteric neurons and glia. This process requires NCCs to undergo proliferation, migration and differentiation to form the complex neuroglial network that regulates gut motility and other intestinal functions. This review discusses the cellular and molecular processes that control normal ENS formation and what goes awry to give rise to HSCR. The complex pathophysiologic consequences of aganglionosis are discussed, including recent observations that describe novel aspects of HSCR beyond the absence of ganglion cells. This review aims to expand the understanding of HSCR and to stimulate new ideas on how to improve current management of the disease.

Atypical Presentation of Hirschsprung's Disease in an Infant: Challenges in Early Diagnosis and Management of Recurrent Enterocolitis

Hirschsprung's disease is a congenital condition characterized by the absence of ganglion cells in the intestines, leading to bowel obstruction. The lack of ganglion cells disrupts the normal motility of the intestines, causing a functional obstruction. This can lead to enterocolitis, an inflammation of the intestines, which is a serious complication in infants with Hirschsprung's disease. This case report follows a male infant with multiple admissions for recurrent enterocolitis secondary to undiagnosed Hirschsprung's disease with unresolving diarrhea. This study underscores the significance of early diagnosis and management, even in cases of atypical presentation, emphasizing the role of antibiotics, bowel decompression, and surgical intervention. The findings highlight the complexity of managing Hirschsprung's disease and offer insights into tailored approaches for optimizing patient outcomes.

Virus-Triggered Autoimmunity Was Associated With Hirschsprung's Disease Through Activation of Innate Immunity

Background: Hirschsprung's disease (HSCR) is a congenital enteric nervous system (ENS) disorder. Genetics cannot explain most sporadic cases. To explore the relationship between pathogen infection, autoantibodies, innate immune, and HSCR. Methods: Pathogen microarray was conducted in the serum of the prospective neonatal abdominal distension (NAD) cohort, consisting of 56 children followed for at least 6 months until the final diagnosis of HSCR was determined or excluded. We conducted an autoantibody microarray in an HSCR cohort, which is comprised of diagnosed HSCR patients (HSCR) and healthy control subjects (HC). RNA-seq of colon tissues from aganglionic and ganglionic segments of HSCR patients was performed. Results: Experimental results show that the serum lgM and lgG of enterovirus 71 (EV71) were significantly higher in HSCR than in the gastrointestinal dysfunction (GI) group, with a prediagnose value reaching area under the curve (AUC) over 0.76. We discovered that a group of autoantibodies were significantly higher in HSCR including neuronal pentraxin 1 (NPTX1), amyloid, neuron lysate, and myelin-associated oligodendrocytic basic protein (MOBP) than that in the HC group. These four autoantibodies could distinguish HSCR from the HC group, with a combined AUC of over 0.90 using both serum IgG and IgM. Further analysis showed that wide activation of innate immune pathways, including toll-like receptor (TLR) signaling pathway, neutrophil-to-lymphocyte ratio (NLR) signaling pathway, red cell distribution width to lymphocyte ratio (RLR) signaling pathway, and cyclic adenosine monophosphate (cAMP) signaling pathway in aganglionic compared to ganglionic segments of HSCR. Conclusion: This study suggested that virus-triggered autoimmunity may contribute to HSCR through activation of innate immunity, which facilitates the diagnosis and prevention of HSCR.

Enhancement of enteric neural stem cell neurogenesis by glial cell-derived neurotrophic factor in experimental Hirschsprung's disease

PURPOSE

Stem cell therapy offers a promising solution for congenital diseases like Hirschsprung's disease (HSCR). Optimizing stem cell efficacy by modifying the cells and their environment is crucial, but in vitro culture conditions need to be further improved. Glial cell-derived neurotrophic factor (GDNF) plays an important role in neuronal survival, proliferation, migration and differentiation during enteric nervous system (ENS) development. In this study, the effects of GDNF on neurites derived from an Ednrb knockout model were investigated with the aim of enhancing the neurogenic potential of enteric neural crest cells (ENCCs).

METHODS

Neurospheres were generated form Ednrb+/+ (control) and Ednrb-/- mice at embryonic day13.5 (E13.5) with Sox10-green fluorescent protein (Venus) transgenic expression. These neurospheres were cultured in control media and neurospheres from Ednrb-/- were cultured with either control media or media supplemented with GDNF. ENCCs differentiation was assessed using immunofluorescence staining after 18 days.

RESULTS

GDNF-treated Ednrb-/- neurospheres showed increased size and higher density of Sox10-positive ENCCs compared to untreated Ednrb-/- neurospheres. GDNF also enhanced the distribution of both TUJ1-positive neurons and S100-positive glial cells.

CONCLUSION

GDNF effectively enhanced the neurogenic potential of ENCCs from HSCR animal model. This finding is crucial for the development of cell therapy in HSCR.

Extended total colonic aganglionosis and total intestinal aganglionosis: Challenging enemies

AIM

Extended total colonic aganglionosis (ETCA) represents uncommon forms of Hirschsprung disease (HD), with aganglionosis extending into the proximal small bowel. ETCA management is challenging and associated with poor outcomes and high mortality. This study compares management and outcomes of ETCA to more common HD forms.

METHODS

A retrospective cohort of HD patients (2012-2023) from two institutions. Three HD forms were compared: short-segment HD (SSHD, n = 19), long-segment HD or total colonic aganglionosis (LS/TCA, n = 9) and ETCA (n = 7).

RESULTS

Normally innervated segments in ETCA patients ranged 0-70 cm. Median times to first surgery were; ETCA = 3 days versus TCA = 21 days (p = 0.017) and SSHD = 95 days (p < 0.001), respectively. Median number of surgeries were; ETCA = 4, versus TCA = 2 (p = 0.17) and SSHD = 1 (p = 0.002), respectively. All the patients underwent a definitive pull-through procedure, except four ETCA patients with a permanent jejunostomy and residual aganglionic segment of 57-130 cm. ETCA patients had 92% lower odds of enterocolitis (14%) compared to TCA patients (67%, p = 0.054), and comparable odds to SSHD patients (16%, p = 0.92). ETCA mortality was 14%.

CONCLUSION

Extended total colonic aganglionosis patients require earlier and multiple interventions. Leaving an aganglionic segment may be advantageous, without increasing risk for enterocolitis. Tailored surgical treatment and rehabilitation programmes may prevent mortality and need for transplantation.

Colonic atresia and Hirschsprung's disease in a neonate: A case report

INTRODUCTION

Colonic atresia is a rare form of intestinal atresia that can be encountered in neonates. Although uncommon, other disease processes can be found simultaneously including malrotation, additional atresias, gastroschisis, and Hirschsprung's disease.

CASE PRESENTATION

A 2-day-old female neonate with known maternal polysubstance use was found to have colonic atresia on contrast enema after emesis and failure to pass meconium. Abdominal exploration revealed a blind ending cecum with evidence of ischemia along with an atretic transverse colon. An ileocecectomy with end ileostomy and transverse colon mucous fistula creation were performed. After eventual ileostomy reversal at 5 weeks of age, she struggled with intermittent oral intolerance and inconsistent bowel function. Re-exploration with ileostomy and gastrostomy tube placement was performed with additional biopsies revealing Hirschsprung's disease.

CLINICAL DISCUSSION

Concomitant colonic atresia and Hirschsprung's disease is a rare clinical entity that provides challenges in diagnosis and definitive surgical management. The suspected source of atresia in this case was presumed to be due to an intra-uterine vascular accident given maternal polysubstance use. Delays in diagnosis can lead to increased patient morbidity.

CONCLUSION

Even with a clear suspected etiology for colonic atresia, surgeons must maintain a high clinical suspicion for additional pathologies including but not limited to Hirschsprung's disease. Rectal suction biopsies should be performed if clinical suspicion arises for Hirschsprung's disease.

Molecular genetics, therapeutics and RET inhibitor resistance for medullary thyroid carcinoma and future perspectives

Medullary thyroid carcinoma (MTC) is a rare type of thyroid malignancy that accounts for approximately 1-2% of all thyroid cancers (TCs). MTC include hereditary and sporadic cases, the former derived from a germline mutation of rearrangement during transfection (RET) proto-oncogene, whereas somatic RET mutations are frequently present in the latter. Surgery is the standard treatment for early stage MTC, and the 10-year survival rate of early MTC is over 80%. While for metastatic MTC, chemotherapy showing low response rate, and there was a lack of effective systemic therapies in the past. Due to the high risk (ca. 15-20%) of distant metastasis and limited systemic therapies, the 10-year survival rate of patients with advanced MTC was only 10-40% from the time of first metastasis. Over the past decade, targeted therapy for RET has developed rapidly, bringing hopes to patients with advanced and progressive MTC. Two multi-kinase inhibitors (MKIs) including Cabozantinib and Vandetanib have been shown to increase progression-free survival (PFS) for patients with metastatic MTC and have been approved as choices of first-line treatment. However, these MKIs have not prolonged overall survival (OS) and their utility is limited due to high rates of off-target toxicities. Recently, new generation TKIs, including Selpercatinib and Pralsetinib, have demonstrated highly selective efficacy against RET and more favorable side effect profiles, and gained approval as second-line treatment options. Despite the ongoing development of RET inhibitors, the management of advanced and progressive MTC remains challenging, drug resistance remains the main reason for treatment failure, and the mechanisms are still unclear. Besides, new promising therapeutic approaches, such as novel drug combinations and next generation RET inhibitors are under development. Herein, we overview the pathogenesis, molecular genetics and current management approaches of MTC, and focus on the recent advances of RET inhibitors, summarize the current situation and unmet needs of these RET inhibitors in MTC, and provide an overview of novel strategies for optimizing therapeutic effects.

Variability in proliferative and migratory defects in Hirschsprung disease-associated RET pathogenic variants

Despite the extensive genetic heterogeneity of Hirschsprung disease (HSCR; congenital colonic aganglionosis) 72% of patients harbor pathogenic variants in 10 genes that form a gene regulatory network (GRN) controlling the development of the enteric nervous system (ENS). Among these genes, the receptor tyrosine kinase gene RET is the most significant contributor, accounting for pathogenic variants in 12%-50% of patients depending on phenotype. RET plays a critical role in the proliferation and migration of ENS precursors, and defects in these processes lead to HSCR. However, despite the gene's importance in HSCR, the functional consequences of RET pathogenic variants and their mechanism of disease remain poorly understood. To address this, we investigated the proliferative and migratory phenotypes in a RET-dependent neural crest-derived cell line harboring one of five missense (L56M, E178Q, Y791F, S922Y, F998L) or three nonsense (Y204X, R770X, Y981X) pathogenic heterozygous variants. Using a combination of cDNA-based and CRISPR-based PRIME editing coupled with quantitative proliferation and migration assays, we detected significant losses in cell proliferation and migration in three missense (E178Q, S922Y, F998L) and all nonsense variants. Our data suggests that the Y791F variant, whose pathogenicity has been debated, is likely not pathogenic. Importantly, the severity of migration loss did not consistently correlate with proliferation defects, and the phenotypic severity of nonsense variants was independent of their position within the RET protein. This study highlights the necessity and feasibility of targeted functional assays to accurately assess the pathogenicity of HSCR-associated variants, rather than relying solely on machine learning predictions, which could themselves be refined by incorporating such functional data.

Human enteric nervous system progenitor transplantation improves functional responses in Hirschsprung disease patient-derived tissue

OBJECTIVE

Hirschsprung disease (HSCR) is a severe congenital disorder affecting 1:5000 live births. HSCR results from the failure of enteric nervous system (ENS) progenitors to fully colonise the gastrointestinal tract during embryonic development. This leads to aganglionosis in the distal bowel, resulting in disrupted motor activity and impaired peristalsis. Currently, the only viable treatment option is surgical resection of the aganglionic bowel. However, patients frequently suffer debilitating, lifelong symptoms, with multiple surgical procedures often necessary. Hence, alternative treatment options are crucial. An attractive strategy involves the transplantation of ENS progenitors generated from human pluripotent stem cells (hPSCs).

DESIGN

ENS progenitors were generated from hPSCs using an accelerated protocol and characterised, in detail, through a combination of single-cell RNA sequencing, protein expression analysis and calcium imaging. We tested ENS progenitors' capacity to integrate and affect functional responses in HSCR colon, after ex vivo transplantation to organotypically cultured patient-derived colonic tissue, using organ bath contractility.

RESULTS

We found that our protocol consistently gives rise to high yields of a cell population exhibiting transcriptional and functional hallmarks of early ENS progenitors. Following transplantation, hPSC-derived ENS progenitors integrate, migrate and form neurons/glia within explanted human HSCR colon samples. Importantly, the transplanted HSCR tissue displayed significantly increased basal contractile activity and increased responses to electrical stimulation compared with control tissue.

CONCLUSION

Our findings demonstrate, for the first time, the potential of hPSC-derived ENS progenitors to repopulate and increase functional responses in human HSCR patient colonic tissue.

Approach to Constipation in Children: Recommendations for Evaluation and Management

Constipation is common in childhood, and most patients can be successfully managed by their primary care provider. However, some patients will require more specialized management either due to an underlying congenital colorectal disorder such as Hirschsprung disease or anorectal malformation or due to severe functional constipation that is refractory to medical management.

Genomic stress in diseases stemming from defects in the second brain

This review discusses the less-explored realm of DNA damage and repair within the enteric nervous system (ENS), often referred to as the "second brain." While the central nervous system has been extensively studied for its DNA repair mechanisms and associated neuropathologies, the ENS, which can autonomously coordinate gastrointestinal function, experiences unique challenges and vulnerabilities related to its genome integrity. The susceptibility of the ENS to DNA damage is exacerbated by its limited protective barriers, resulting in not only endogenous genotoxic exposures, such as oxidative stress, but also exogenous threats, such as ingested environmental contaminants, local inflammatory responses, and gut dysbiosis. Here, we discuss the evidence for DNA repair defects in enteric neuropathies, most notably, the reported relationship between inherited mutations in RAD21 and LIG3 with chronic intestinal pseudo-obstruction and mitochondrial gastrointestinal encephalomyopathy disorders, respectively. We also introduce the lesser-recognized gastrointestinal complications in DNA repair syndromes, including conditions like Cockayne syndrome. The review concludes by pointing out the potential role of DNA repair defects in not only congenital disorders but also aging-related gut dysfunction, as well as the crucial need for further research to establish direct causal links between DNA damage accumulation and ENS-specific pathologic phenotypes.

Hirschsprung's disease. Management

BACKGROUND

Hirschsprung's disease (HD) is a rare congenital disease that is characterised by the absence of ganglion cells in the myenteric plexus starting in the distal bowel. This results in distal functional obstruction and may lead to complications like enterocolitis. The treatment is surgical and requires the resection of the aganglionic segment, and the pull-through of normal intestine into the anal opening. However, even after successful surgery, patients may continue to have symptoms.

AIM

Discuss current surgical techniques and management strategies for patients with postoperative symptoms after surgical correction of Hirschsprung's disease.

METHODS

A review of the literature was done through PubMed, with a focus on clinical management and approach.

RESULTS

We describe the clinical problems that can occur after surgical correction. These include obstructive symptoms, enterocolitis, or faecal incontinence. A systematic approach for the evaluation of these patients includes the exclusion of anatomic, inflammatory, behavioural or motility related factors. Depending on the severity of the symptoms, the evaluation includes examination under anaesthesia, the performance of contrast studies, endoscopic studies, measurement of anal sphincter function and colonic motility studies. The treatment is focused towards addressing the different pathophysiological mechanisms, and may include medical management, botulinum toxin to the anal sphincter or rarely redo-operation.

CONCLUSIONS

Patients with Hirschsprung's disease need to have surgical correction, and their postoperative long-term management is complex given a variety of associated problems that can occur after surgery. A systematic evaluation is necessary to provide appropriate therapy.

Toll-like receptor-8 mRNA expression as a predictor of enterocolitis in hirschsprung disease: a cross-sectional study

Introduction:

Hirschsprung-associated enterocolitis (HAEC) is an inflammatory intestinal condition occurring in patients with Hirschsprung disease (HD). While the exact pathogenesis remains unclear, factors such as intestinal mucosal barrier injury, abnormal immune responses, and pathogenic infections contribute to HAEC. Toll-like receptors (TLRs) 7 and 8 are key in viral recognition and correlate with intestinal mucosal inflammation. In particular, TLR-8 contributes to antiviral responses, and chronic inflammation, and can be targeted with adjuvants. This study investigates the relationship between TLR-8 mRNA expression and enterocolitis in HD.

Methods:

This cross-sectional study utilized simple random sampling. Histopathological analysis of colon samples from HD patients was used to assess enterocolitis severity, and RT-PCR quantified TLR-8 mRNA expression. HD diagnosis was confirmed via rectal biopsy, and enterocolitis was graded using Teitelbaum’s classification.

Results:

The study included 29 patients with an average age of 4.8 years. TLR-8 mRNA expression averaged 8.5 (fold change), ranging from 6.5 to 13.8. Subjects were divided into low (≤8.1) and high (>8.1) expression groups, with 15 (51.7%) and 14 (48.3%) patients, respectively. Enterocolitis severity distribution was 22 (75.9%) normal, 1 (3.4%) grade II, 4 (13.8%) grade III, and 2 (6.9%) IV.

Conclusion:

There is a significant association between TLR-8 mRNA expression and the incidence of enterocolitis in patients with HD. The authors found that increased TLR-8 mRNA expression in HD patients resulted in a twofold higher risk of enterocolitis. Altogether, our data indicates the potential for TLR-8 mRNA expression in biopsies as an indicator of the risk of enterocolitis development in patients with HD.

Further description of two individuals with de novo p.(Glu127Lys) missense variant in the ASCL1 gene

Achaete-Scute Family basic-helix-loop-helix (bHLH) Transcription Factor 1 (ASCL1) is a proneural transcription factor involved in neuron development in the central and peripheral nervous system. While initially suspected to contribute to congenital central hypoventilation syndrome-1 (CCHS) with or without Hirschsprung disease (HSCR) in three individuals, its implication was ruled out by the presence, in one of the individuals, of a Paired-like homeobox 2B (PHOX2B) heterozygous polyalanine expansion variant, known to cause CCHS. We report two additional unrelated individuals sharing the same sporadic ASCL1 p.(Glu127Lys) missense variant in the bHLH domain and a common phenotype with short-segment HSCR, signs of dysautonomia, and developmental delay. One has also mild CCHS without polyalanine expansion in PHOX2B, compatible with the diagnosis of Haddad syndrome. Furthermore, missense variants with homologous position in the same bHLH domain in other genes are known to cause human diseases. The description of additional individuals carrying the same variant and similar phenotype, as well as targeted functional studies, would be interesting to further evaluate the role of ASCL1 in neurocristopathies.

Gastrointestinal Dysmotility Predisposes to Colitis through Regulation of Gut Microbial Composition and Linoleic Acid Metabolism

Disrupted gastrointestinal (GI) motility is highly prevalent in patients with inflammatory bowel disease (IBD), but its potential causative role remains unknown. Herein, the role and the mechanism of impaired GI motility in colitis pathogenesis are investigated. Increased colonic mucosal inflammation is found in patients with chronic constipation (CC). Mice with GI dysmotility induced by genetic mutation or chemical insult exhibit increased susceptibility to colitis, dependent on the gut microbiota. GI dysmotility markedly decreases the abundance of Lactobacillus animlalis and increases the abundance of Akkermansia muciniphila. The reduction in L. animlalis, leads to the accumulation of linoleic acid due to compromised conversion to conjugated linoleic acid. The accumulation of linoleic acid inhibits Treg cell differentiation and increases colitis susceptibility via inducing macrophage infiltration and proinflammatory cytokine expression in macrophage. Lactobacillus and A. muciniphila abnormalities are also observed in CC and IBD patients, and mice receiving fecal microbiota from CC patients displayed an increased susceptibility to colitis. These findings suggest that GI dysmotility predisposes host to colitis development by modulating the composition of microbiota and facilitating linoleic acid accumulation. Targeted modulation of microbiota and linoleic acid metabolism may be promising to protect patients with motility disorder from intestinal inflammation.

Unraveling the Promise of RET Inhibitors in Precision Cancer Therapy by Targeting RET Mutations

Over the past decades, the role of rearranged during transfection (RET) alterations in tumorigenesis has been firmly established. RET kinase inhibition is an essential therapeutic target in patients with RET-altered cancers. In clinical practice, initial efficacy can be achieved in patients through the utilization of multikinase inhibitors (MKIs) with RET inhibitory activity. However, the effectiveness of these MKIs is impeded by the adverse events associated with off-target effects. Recently, many RET-selective inhibitors, characterized by heightened specificity and potency, have been developed, representing a substantial breakthrough in the field of RET precision oncology. This Perspective focuses on the contemporary understanding of RET mutations, recent advancements in next-generation RET inhibitors, and the challenges associated with resistance to RET inhibitors. It provides valuable insights for the development of next-generation MKIs and selective RET inhibitors.

Enteric Nervous System Striped Patterning and Disease: Unexplored Pathophysiology

The enteric nervous system (ENS) controls gastrointestinal (GI) motility, and defects in ENS development underlie pediatric GI motility disorders. In disorders such as Hirschsprung's disease (HSCR), pediatric intestinal pseudo-obstruction (PIPO), and intestinal neuronal dysplasia type B (INDB), ENS structure is altered with noted decreased neuronal density in HSCR and reports of increased neuronal density in PIPO and INDB. The developmental origin of these structural deficits is not fully understood. Here, we review the current understanding of ENS development and pediatric GI motility disorders incorporating new data on ENS structure. In particular, emerging evidence demonstrates that enteric neurons are patterned into circumferential stripes along the longitudinal axis of the intestine during mouse and human development. This novel understanding of ENS structure proposes new questions about the pathophysiology of pediatric GI motility disorders. If the ENS is organized into stripes, could the observed changes in enteric neuron density in HSCR, PIPO, and INDB represent differences in the distribution of enteric neuronal stripes? We review mechanisms of striped patterning from other biological systems and propose how defects in striped ENS patterning could explain structural deficits observed in pediatric GI motility disorders.

ATP5PO levels regulate enteric nervous system development in zebrafish, linking Hirschsprung disease to Down Syndrome

Hirschsprung disease (HSCR) is a complex genetic disorder characterized by the absence of enteric nervous system (ENS) in the distal region of the intestine. Down Syndrome (DS) patients have a >50-fold higher risk of developing HSCR than the general population, suggesting that overexpression of human chromosome 21 (Hsa21) genes contribute to HSCR etiology. However, identification of responsible genes remains challenging. Here, we describe a genetic screening of potential candidate genes located on Hsa21, using the zebrafish. Candidate genes were located in the DS-HSCR susceptibility region, expressed in the human intestine, were known potential biomarkers for DS prenatal diagnosis, and were present in the zebrafish genome. With this approach, four genes were selected: RCAN1, ITSN1, ATP5PO and SUMO3. However, only overexpression of ATP5PO, coding for a component of the mitochondrial ATPase, led to significant reduction of ENS cells. Paradoxically, in vitro studies showed that overexpression of ATP5PO led to a reduction of ATP5PO protein levels. Impaired neuronal differentiation and reduced mitochondrial ATP production, were also detected in vitro, after overexpression of ATP5PO in a neuroblastoma cell line. Finally, epistasis was observed between ATP5PO and ret, the most important HSCR gene. Taken together, our results identify ATP5PO as the gene responsible for the increased risk of HSCR in DS patients in particular if RET variants are also present, and show that a balanced expression of ATP5PO is required for normal ENS development.

Genetic regulation of enteric nervous system development in zebrafish

The enteric nervous system (ENS) is a complex series of interconnected neurons and glia that reside within and along the entire length of the gastrointestinal tract. ENS functions are vital to gut homeostasis and digestion, including local control of peristalsis, water balance, and intestinal cell barrier function. How the ENS develops during embryological development is a topic of great concern, as defects in ENS development can result in various diseases, the most common being Hirschsprung disease, in which variable regions of the infant gut lack ENS, with the distal colon most affected. Deciphering how the ENS forms from its progenitor cells, enteric neural crest cells, is an active area of research across various animal models. The vertebrate animal model, zebrafish, has been increasingly leveraged to understand early ENS formation, and over the past 20 years has contributed to our knowledge of the genetic regulation that underlies enteric development. In this review, I summarize our knowledge regarding the genetic regulation of zebrafish enteric neuronal development, and based on the most current literature, present a gene regulatory network inferred to underlie its construction. I also provide perspectives on areas for future zebrafish ENS research.

High-Resolution Anorectal Manometry as a Screening Tool for Hirschsprung's Disease: A Comprehensive Retrospective Analysis

Hirschsprung's disease (HD) is characterized by a congenital absence of enteric ganglion cells in the intestine, posing challenges in diagnosis, particularly in pediatric patients. The gold standard, rectal suction biopsy (RSB), carries risks, prompting an exploration of non-invasive alternatives such as high-resolution anorectal manometry (HR-ARM) for HD screening. We conducted a retrospective analysis of 136 patients suspected of HD between 2018 and 2022, which were stratified into three age groups: ≤12 months, ≤24 months, and >24 months. Criteria for suspicion included delayed meconium passage, unresponsive chronic constipation, and abnormal prior test results. HR-ARM, supplemented by additional tests, confirmed 16 HD cases. HR-ARM exhibited 93.75% sensitivity, 89.47% specificity, 99.03% negative predictive value (NPV), and 55.56% positive predictive value (PPV). Notably, HR-ARM consistently performed well in patients ≤ 2 years old but demonstrated reduced efficacy in older children, which was likely due to complications from chronic constipation. This study underscores HR-ARM's promise as a non-invasive HD screening tool, especially in younger patients. However, its limitations in older children warrant consideration. Establishing standardized protocols, particularly for assessing the recto-anal inhibitory reflex, is crucial. Further research is imperative to optimize HR-ARM's diagnostic role across varied age groups in HD assessment.

A Rare Case Report on Postoperative Rehabilitation in Hirschsprung Disease

Hirschsprung disease (HD) is characterized by the absence of ganglion cells in the myenteric and submucosal plexuses of the hindgut. Here, we report a case of an eight-year-old male child who had abdominal distension with a history of repetitive gas passage and a complaint of stool passage. In February 2023, the patient was diagnosed with Hirshsprung disease, for which a left-side colostomy was done. In November 2023, he underwent Hirshsprung stage 2 repair. He was operated on the 17th of December 2023 under general anaesthesia colostomy mobilization. Physiotherapy commencement and evaluation were started on the 18th of December 2023. After the colostomy procedure, the incision weakened the abdominal and lower limb muscles, while bowel obstruction and discomfort further impeded the patient's ability to perform daily activities. Physical examination revealed increased work of breathing, reduced range of motion of the bilateral hip joint, reduced muscle strength of lower limb musculature, reduced abdominal muscle strength, difficulty in walking and waddling type of gait. Physiotherapy goals were set based on the problem list. The patient showed improvement in the two weeks of physiotherapy commencement, followed by improvement in functional ability. The comprehensive care provided during the rehabilitation phase aimed at addressing the specific needs arising from the surgical intervention, promoting optimal bowel function, improving ranges and strength and ensuring overall well-being.

The role of Down syndrome cell adhesion molecule in Down syndrome

Down syndrome (DS) is caused by the presence of an extra copy of the entire or a portion of human chromosome 21 (HSA21). This genomic alteration leads to elevated expression of numerous HSA21 genes, resulting in a variety of health issues in individuals with DS. Among the genes located in the DS "critical region" of HSA21, Down syndrome cell adhesion molecule (DSCAM) plays an important role in neuronal development. There is a growing body of evidence underscoring DSCAM's involvement in various DS-related disorders. This review aims to provide a concise overview of the established functions of DSCAM, with a particular focus on its implications in DS. We delve into the roles that DSCAM plays in DS-associated diseases. In the concluding section of this review, we explore prospective avenues for future research to further unravel DSCAM's role in DS and opportunities for therapeutic treatments.

High incidence of EDNRB gene mutation in seven southern Chinese familial cases with Hirschsprung's disease

PURPOSE

Hirschsprung's disease (HSCR) is the leading cause of neonatal functional intestinal obstruction, which has been identified in many familial cases. HSCR, a multifactorial disorder of enteric nervous system (ENS) development, is associated with at least 24 genes and seven chromosomal loci, with RET and EDNRB as its major genes. We present a genetic investigation of familial HSCR to clarify the genotype-phenotype relationship.

METHODS

We performed whole exome sequencing (WES) on Illumina HiSeq X Ten platform to investigate genetic backgrounds of core family members, and identified the possibly harmful mutation genes. Mutation carriers and pedigree relatives were validated by Sanger sequencing for evaluating the gene penetrance.

RESULTS

Four familial cases showed potential disease-relative variants in EDNRB and RET gene, accounting for all detection rate of 57.1%. Three familial cases exhibited strong pathogenic variants as frameshift or missense mutations in EDNRB gene. A novel c.367delinsTT mutation of EDNRB was identified in one family member. The other two EDNRB mutations, c.553G>A in family 2 and c.877delinsTT in family 5, have been reported in previous literatures. The penetrance of EDNRB variants was 33-50% according mutation carries. In family 6, the RET c.1858T>C (C620R) point mutation has previously been reported to cause HSCR, with 28.5% penetrance.

CONCLUSION

We identified a novel EDNRB (deleted C and inserted TT) mutation in this study using WES. Heterozygote variations in EDNRB gene were significantly enriched in three families and RET mutations were identified in one family. EDNRB variants showed an overall higher incidence and penetrance than RET in southern Chinese families cases.

Chronic intestinal pseudo-obstruction in adults: A practical guide to identify patient subgroups that are suitable for more specific treatments

Chronic intestinal pseudo-obstruction is a rare and heterogeneous syndrome characterized by recurrent symptoms of intestinal obstruction with radiological features of dilated small or large intestine with air/fluid levels in the absence of any mechanical occlusive lesion. Several diseases may be associated with chronic intestinal pseudo-obstruction and in these cases, the prognosis and treatment are related to the underlying disease. Also, in its "primary or idiopathic" form, two subgroups of patients should be determined as they require a more specific therapeutic approach: patients whose chronic intestinal pseudo-obstruction is due to sporadic autoimmune/inflammatory mechanisms and patients whose neuromuscular changes are genetically determined. In a context of a widely heterogeneous adult population presenting chronic intestinal pseudo-obstruction, this review aims to summarize a practical diagnostic workup for identifying definite subgroups of patients who might benefit from more specific treatments, based on the etiology of their underlying condition.

Endothelin signaling in development

Since the discovery of endothelin 1 (EDN1) in 1988, the role of endothelin ligands and their receptors in the regulation of blood pressure in normal and disease states has been extensively studied. However, endothelin signaling also plays crucial roles in the development of neural crest cell-derived tissues. Mechanisms of endothelin action during neural crest cell maturation have been deciphered using a variety of in vivo and in vitro approaches, with these studies elucidating the basis of human syndromes involving developmental differences resulting from altered endothelin signaling. In this Review, we describe the endothelin pathway and its functions during the development of neural crest-derived tissues. We also summarize how dysregulated endothelin signaling causes developmental differences and how this knowledge may lead to potential treatments for individuals with gene variants in the endothelin pathway.

Short and Long-Term Outcomes in Hirschsprung Disease: Are the Syndrome-Associated Patients Really Doing Worse?

INTRODUCTION

Given the lack of data to help caregivers in the follow-up of Hirschsprung disease (HD), this study aimed to compare the functional outcomes of isolated Hirschsprung disease (I-HD) to syndrome-associated Hirschsprung disease (SA-HD) at 1, 3, 5, and 10 years.

METHODS

A retrospective chart review of patients diagnosed with HD between January 1990 and May 2021 at our pediatric center was performed to collect data on patient characteristics, investigations, and treatments. Ninety-five patients were identified, of whom 76 were included in the study. SA-HD is defined as a syndrome known to be associated with HD or cognitive impairment.

RESULTS

Patient characteristics were comparable between groups ( P > 0.05). There were 52 patients with I-HD and 24 with SA-HD. The patients median age was 9 days at diagnosis and 1.5 month at surgery. SA-HD patients became bowel continent at a significantly older age (mean age 8.43 vs 4.94 years, P = 0.0471) and received more bowel continence medications. At 5 years, SA-HD patients requiring ≥2 medications for bowel continence represented 54.5% versus 11.1% of I-HD patients ( P = 0.009). Lastly, SA-HD patients had urinary incontinence at a significantly older age ( P = 0.0136, 5 years).

CONCLUSION

Clinicians should be aware that SA-HD patients are more prone to bladder dysfunction and became bowel continent at an older age than I-HD patients. They need more and prolonged bowel management medications, and other important complications need to be addressed in patient care. These results should prompt a longer follow-up period for these patients, especially in SA-HD.

Single-cell profiling coupled with lineage analysis reveals vagal and sacral neural crest contributions to the developing enteric nervous system

During development, much of the enteric nervous system (ENS) arises from the vagal neural crest that emerges from the caudal hindbrain and colonizes the entire gastrointestinal tract. However, a second ENS contribution comes from the sacral neural crest that arises in the caudal neural tube and populates the post-umbilical gut. By coupling single-cell transcriptomics with axial-level-specific lineage tracing in avian embryos, we compared the contributions of embryonic vagal and sacral neural crest cells to the chick ENS and the associated peripheral ganglia (Nerve of Remak and pelvic plexuses). At embryonic day (E) 10, the two neural crest populations form overlapping subsets of neuronal and glia cell types. Surprisingly, the post-umbilical vagal neural crest much more closely resembles the sacral neural crest than the pre-umbilical vagal neural crest. However, some differences in cluster types were noted between vagal and sacral derived cells. Notably, RNA trajectory analysis suggests that the vagal neural crest maintains a neuronal/glial progenitor pool, whereas this cluster is depleted in the E10 sacral neural crest which instead has numerous enteric glia. The present findings reveal sacral neural crest contributions to the hindgut and associated peripheral ganglia and highlight the potential influence of the local environment and/or developmental timing in differentiation of neural crest-derived cells in the developing ENS.

Hirschsprung disease

Hirschsprung disease (HSCR) is a rare congenital intestinal disease that occurs in 1 in 5,000 live births. HSCR is characterized by the absence of ganglion cells in the myenteric and submucosal plexuses of the intestine. Most patients present during the neonatal period with the first meconium passage delayed beyond 24 h, abdominal distension and vomiting. Syndromes associated with HSCR include trisomy 21, Mowat-Wilson syndrome, congenital central hypoventilation syndrome, Shah-Waardenburg syndrome and cartilage-hair hypoplasia. Multiple putative genes are involved in familial and isolated HSCR, of which the most common are the RET proto-oncogene and EDNRB. Diagnosis consists of visualization of a transition zone on contrast enema and confirmation via rectal biopsy. HSCR is typically managed by surgical removal of the aganglionic bowel and reconstruction of the intestinal tract by connecting the normally innervated bowel down to the anus while preserving normal sphincter function. Several procedures, namely Swenson, Soave and Duhamel procedures, can be undertaken and may include a laparoscopically assisted approach. Short-term and long-term comorbidities include persistent obstructive symptoms, enterocolitis and soiling. Continued research and innovation to better understand disease mechanisms holds promise for developing novel techniques for diagnosis and therapy, and improving outcomes in patients.

Macrophage regulation of the "second brain": CD163 intestinal macrophages interact with inhibitory interneurons to regulate colonic motility - evidence from the Cx3cr1-Dtr rat model

Intestinal macrophages are well-studied for their conventional roles in the immune response against pathogens and protecting the gut from chronic inflammation. However, these macrophages may also have additional functional roles in gastrointestinal motility under typical conditions. This is likely to occur via both direct and indirect influences on gastrointestinal motility through interaction with myenteric neurons that contribute to the gut-brain axis, but this mechanism is yet to be properly characterised. The CX3CR1 chemokine receptor is expressed in the majority of intestinal macrophages, so we used a conditional knockout Cx3cr1-Dtr (diphtheria toxin receptor) rat model to transiently ablate these cells. We then utilized ex vivo video imaging to evaluate colonic motility. Our previous studies in brain suggested that Cx3cr1-expressing cells repopulate by 7 days after depletion in this model, so we performed our experiments at both the 48 hr (macrophage depletion) and 7-day (macrophage repopulation) time points. We also investigated whether inhibitory neuronal input driven by nitric oxide from the enteric nervous system is required for the regulation of colonic motility by intestinal macrophages. Our results demonstrated that CD163-positive resident intestinal macrophages are important in regulating colonic motility in the absence of this major inhibitory neuronal input. In addition, we show that intestinal macrophages are indispensable in maintaining a healthy intestinal structure. Our study provides a novel understanding of the interplay between the enteric nervous system and intestinal macrophages in colonic motility. We highlight intestinal macrophages as a potential therapeutic target for gastrointestinal motility disorders when inhibitory neuronal input is suppressed.

L1cam alternative shorter transcripts encoding the extracellular domains were overexpressed in the intestine of L1cam knockdown mice

Hirschsprung disease (HSCR) is a congenital disorder of functional bowel obstruction due to the absence of enteric ganglia in distal bowel. Different L1cam variants were reportedly associated with L1cam syndrome and HSCR, whose phenotypes lacked predictable relevance to their genotypes. Using next-generation sequencing (NGS), we found an L1CAM de novo frameshift mutation in a female with mild hydrocephalus and skip-type HSCR. A nearly identical L1cam variant was introduced into FVB/NJ mice via the CRISPR-EZ method. A silent mutation was created via ssODN to gain an artificial Ncol restriction enzyme site for easier genotyping. Six L1cam protein-coding alternative transcripts were quantitatively measured. Immunofluorescence staining with polyclonal and monoclonal L1cam antibodies was used to characterize L1cam isoform proteins in enteric ganglia. Fifteen mice, seven males and eight females, generated via CRISPR-EZ, were confirmed to carry the L1cam frameshift variant, resulting in a premature stop codon. There was no prominent hydrocephalus nor HSCR-like presentation in these mice, but male infertility was noticed after observation for three generations in a total of 176 mice. Full-length L1cam transcripts were detected at a very low level in the intestinal tissues and almost none in the brain of these mice. Alternative shorter transcripts encoding the extracellular domains were overexpressed in the intestine of L1cam knockdown mice. Immunofluorescence confirmed no fulllength L1cam protein in enteric ganglia. These shorter L1cam isoform proteins might play a role in protecting L1cam knockdown mice from HSCR.

A branching model of lineage differentiation underpinning the neurogenic potential of enteric glia

Glial cells have been proposed as a source of neural progenitors, but the mechanisms underpinning the neurogenic potential of adult glia are not known. Using single cell transcriptomic profiling, we show that enteric glial cells represent a cell state attained by autonomic neural crest cells as they transition along a linear differentiation trajectory that allows them to retain neurogenic potential while acquiring mature glial functions. Key neurogenic loci in early enteric nervous system progenitors remain in open chromatin configuration in mature enteric glia, thus facilitating neuronal differentiation under appropriate conditions. Molecular profiling and gene targeting of enteric glial cells in a cell culture model of enteric neurogenesis and a gut injury model demonstrate that neuronal differentiation of glia is driven by transcriptional programs employed in vivo by early progenitors. Our work provides mechanistic insight into the regulatory landscape underpinning the development of intestinal neural circuits and generates a platform for advancing glial cells as therapeutic agents for the treatment of neural deficits.

Should primary anastomosis be considered more? A retrospective analysis of anastomotic complications in young children

Objective

Little is known about intestinal anastomotic leakage and stenosis in young children (≤3 years of age). The purpose of this study is to answer the following questions: (1) what is the incidence of anastomotic stenosis and leakage in infants? (2) which surgical diseases entail the highest incidence of anastomotic stenosis and leakage? (3) what are perioperative factors associated with anastomotic stenosis and leakage?

Methods

Patients who underwent an intestinal anastomosis during primary abdominal surgery in our tertiary referral centre between 1998 and 2018 were retrospectively included. Both general incidence and incidence per disease of anastomotic complications were determined. Technical risk factors (location and type of anastomosis, mode of suturing, and suture resorption time) were evaluated by multivariate Cox regression for anastomotic stenosis. Gender and American Society of Anaesthesiology (ASA) score of ≥III were evaluated by χ2 test for anastomotic leakage.

Results

In total, 477 patients underwent an anastomosis. The most prominent diseases are intestinal atresia (30%), Hirschsprung's disease (29%), and necrotizing enterocolitis (14%). Anastomotic stenosis developed in 7% (34/468) of the patients with highest occurrence in necrotizing enterocolitis (14%, 9/65). Colonic anastomosis was associated with an increased risk of anastomotic stenosis (hazard ratio (HR) =3.6, 95% CI 1.8 to 7.5). No technical features (type of anastomosis, suture resorption time and mode of suturing) were significantly associated with stenosis development. Anastomotic leakage developed in 5% (22/477) of the patients, with the highest occurrence in patients with intestinal atresia (6%, 9/143). An ASA score of ≥III (p=0.03) and male gender (p=0.03) were significantly associated with anastomotic leakage.

Conclusions

Both anastomotic stenosis and leakage are major surgical complications. Identifying more patient specific factors can result in better treatment selection, which should not solely be based on the type of disease.

Transcriptome profiling of intact bowel wall reveals that PDE1A and SEMA3D are possible markers with roles in enteric smooth muscle apoptosis, proliferative disorders, and dysautonomia in Crohn's disease

Background: Inflammatory bowel disease (IBD) is a complex and multifactorial inflammatory condition, comprising Crohn's disease (CD) and ulcerative colitis (UC). While numerous studies have explored the immune response in IBD through transcriptional profiling of the enteric mucosa, the subtle distinctions in the pathogenesis of Crohn's disease and ulcerative colitis remain insufficiently understood. Methods: The intact bowel wall specimens from IBD surgical patients were divided based on their inflammatory status into inflamed Crohn's disease (iCD), inflamed ulcerative colitis (iUC) and non-inflamed (niBD) groups for RNA sequencing. Differential mRNA GO (Gene Ontology), and KEGG (Kyoto Encyclopedia of Genes and Genomes), and GSEA (Gene Set Enrichment Analysis) bioinformatic analyses were performed with a focus on the enteric autonomic nervous system (ANS) and smooth muscle cell (SMC). The transcriptome results were validated by quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC). Results: A total of 2099 differentially expressed genes were identified from the comparison between iCD and iUC. Regulation of SMC apoptosis and proliferation were significantly enriched in iCD, but not in iUC. The involved gene PDE1A in iCD was 4-fold and 1.5-fold upregulated at qPCR and IHC compared to that in iUC. Moreover, only iCD was significantly associated with the gene sets of ANS abnormality. The involved gene SEMA3D in iCD was upregulated 8- and 5-fold at qPCR and IHC levels compared to iUC. Conclusion: These findings suggest that PDE1A and SEMA3D may serve as potential markers implicated in enteric smooth muscle apoptosis, proliferative disorders, and dysautonomia specifically in Crohn's disease.